OBJECTIVES: You will build a simple wind tunnel and test out 2 glider wing shapes at different angles of attack. You will record your observations and results just as engineers do. There also is a "virtual wind tunnel" you can try and see how the aerodynamics changes with wing shape and angle of attack. STEPS TO FOLLOW: Review the information in the background section. Make the two gliders. Print out the two glider patterns - straight wing and sweptback wing. Trace the glider patterns onto the tag board or balsa wood. Note: the pattern is designed for tag board. When using balsa wood, reduce the size of the wing and elevator (tail) opening slightly (make the openings a little smaller). Using the safety scissors or craft knife cut out the glider patterns. Assemble the glider. STRAIGHT WING GLIDER SWEPTBACK WING GLIDER To make the balance: Cut an opening in the middle of the shoebox cover. The opening should have the same height and width as the yardstick (or whatever long stick you use). Cut an opening in the bottom of the shoebox, 9 " high and the same width and height of the yardstick (or whatever long stick you are using).

MATERIALS: Shoebox Tag Board or 1/16" Balsa Wood 9" Fishing Line, Light Weight String, or Thick Thread Pencil or Pen Clear Tape Safety Scissors Small Protractor Flat Wood Trim, Approximately 1/4" thick, 3/4" Wide and 36" Long; or a Light Weight Wooden Yardstick or Dowel 36" Long Craft Knife Electric Fan Stapler Small Amount of Clay or a Washer Stand the shoebox on one of the short sides. Tape a protractor at the lower edge of the bottom of the shoe box. Place a small amount of clay (or the weight) at one end of the string. Center the other end of the string and tape or staple it between the slot and the protractor. This serves as a plumb line (a line which is directed straight down.) Securely tape the top of the shoebox to the bottom. Insert the yardstick through the small hole in the top and through the long slot in the bottom of the shoebox. Tape one of the gliders to the free end of the yardstick (the side not inserted in the box). Notice that by moving the shoebox you can change the angle of attack of the glider. Turn the fan on. Stand to the side of the fan. Holding the box, place the glider and yardstick into the fan's airstream, until the glider and yardstick lift into the air. You can move the box around to change the angle of attack of the glider. Look at the angle that the plumb line makes with the protractor. Record the angle at which the glider begins to lift. Repeat the experiment with the other glider. If you have used a balsa wood glider try and bend the wings down at the tips - does this change the lift angle?